Fusionfire
Hazard to Others
Posts: 219
Registered: 8-7-2011
Member Is Offline
Mood: No Mood
|
|
C2H2 without CaC2?
What are the alternative synthesis routes for acetylene gas that do not involve calcium carbide?
I only require a small quantity of acetylene but I seem to be having difficulty sourcing acetylene or calcium carbide in less than commercial
quantities in the UK.
Would you be able to make improvised CaC2 by sending high voltage electrical pulses through a mixture of carbon + calcium oxide in a borosilicate
tube?
|
|
|
Megamarko94
Hazard to Self
Posts: 68
Registered: 31-12-2010
Member Is Offline
Mood: No Mood
|
|
i dont know any other way of making acetylene..
and if you want to make CaC2 yourself you need temp. over 2000c* so i dont think that borosilicate tube will handle that temp.
|
|
|
Fusionfire
Hazard to Others
Posts: 219
Registered: 8-7-2011
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Megamarko94  | | and if you want to make CaC2 yourself you need temp. over 2000c* so i dont think that borosilicate tube will handle that temp. |
The highest temperatures will be at the arc points but I consider the container to be disposable after a few uses. A cheaper and more acceptable
sacrificial vessel may be made from fire clay.
|
|
|
ScienceSquirrel
International Hazard
Posts: 1863
Registered: 18-6-2008
Location: Brittany
Member Is Offline
Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
|
|
Thre are descriptions on the Internet of making small amounts of calcium carbide using a welder.
The best idea is to keep an eye on eBay, sometimes a few hundred grams comes up for a few pounds.
That lasts a long time for small experiments.
|
|
|
smuv
National Hazard
Posts: 842
Registered: 2-5-2007
Member Is Offline
Mood: Jingoistic
|
|
KOH/Ethanol vinyl chloride.
KOH/Ethanol ethylene bromide.
*probably*KOH/Ethanol ethylene chloride *haven't checked lit on this one*
Many other ways but these are the least brute force methods. Vapor phase methods allow acetylene to be made from many substrates, but these require
high temps. Although, acetylene is very otc if you are willing to rent/buy the tank (or as ScienceSquirrel pointed out, buy CaC2).
"Titanium tetrachloride…You sly temptress." --Walter Bishop
|
|
|
Fusionfire
Hazard to Others
Posts: 219
Registered: 8-7-2011
Member Is Offline
Mood: No Mood
|
|
There's this seller in the Czech Republic:
http://www.ebay.co.uk/itm/Calcium-Carbide-Stones-Carbide-Lam...
But given that both his photos use Wikipedia's pictures, I am suspicious.
|
|
|
Mailinmypocket
International Hazard
Posts: 1351
Registered: 12-5-2011
Member Is Offline
Mood: No Mood
|
|
I have actually bought from this seller very recently, it was cheap and shipping was surprisingly also cheap... Sounded too good to he true but... I
got my stuff wrapped tightly in plastic wrap and in a zip lock type bag... Big chunks though... Get your hammer ready...took 6 days to receive and I'm
in Ontario, Canada ..
I checked his feedback before buying and it's very positive btw..
|
|
|
Fusionfire
Hazard to Others
Posts: 219
Registered: 8-7-2011
Member Is Offline
Mood: No Mood
|
|
OK thanks for letting me know, I'll buy some CaC2 from him rather than make my own by electric discharge...for now  . A few hundred grams is plenty to make silver acetylide - too costly to make in any
large quantity!
What I like about electric discharge through CaO + C is that not only are the raw materials dirt cheap, you don't have to fiddle about to get pure
CaC2 if you're just after acetylene - just add water 
|
|
|
The WiZard is In
International Hazard
Posts: 1617
Registered: 3-4-2010
Member Is Offline
Mood: No Mood
|
|
There dobe 'bout 6, however, I don't think you will be
able to use them.
Took me The Analogue Guy 2 minutes looking a book
to find them. A digital person using
www.justfuckinggoogleit.com could probable do it faster.
I found a 977 page book on acetylene among others searching
online.
|
|
|
Otter
Harmless
Posts: 23
Registered: 5-8-2011
Location: Shrewsbury, Massachusetts, USA
Member Is Offline
Mood: Pensieve
|
|
| Quote: Originally posted by Fusionfire | What are the alternative synthesis routes for acetylene gas that do not involve calcium carbide?
I only require a small quantity of acetylene but I seem to be having difficulty sourcing acetylene or calcium carbide in less than commercial
quantities in the UK.
Would you be able to make improvised CaC2 by sending high voltage electrical pulses through a mixture of carbon + calcium oxide in a borosilicate
tube? |
What you can try is to react 1,2 dichloroethane with sodium amide. 1 equivalent of 1,2 dichloroethane will need 2 equivalents of sodium amide.
However sodium amide is incredibly reactive, it will definitely react with moisture in the air as the amides convert to ammonia by deprotonating
water.
So many gases are tricky to work with.
Best stick with CaC2 and water. 
*Otter sniffs the puddle.*
*Licks a tiny bit of it up.*
*Pukes out dinner.*
|
|
|
497
National Hazard
Posts: 778
Registered: 6-10-2007
Member Is Offline
Mood: HSbF6
|
|
The alternative that looked most interesting to me was microwave induced plasma pyrolysis of methane (maybe mixed with inert gas). I read a very
informative paper on it, which I don't have a link to, but it shouldn't be too tough to find. They found that rapid cooling was critical to avoid the
decomposition of the acetylene. They devised a surprisingly simple venturi cooler system that was able to achieve cooling at 10 to the 5th K/second
and subsequently yielded acetylene at an efficiency competitative with commercial production at the time. A microwave oven transformer could yield a
hell of a lot of acetylene if the experiment is repeatable. More accessable alkanes like propane may also give yields..
|
|
|
Fantasma4500
International Hazard
Posts: 1681
Registered: 12-12-2012
Location: Dysrope (aka europe)
Member Is Offline
Mood: dangerously practical
|
|
i have thought about making CaC2 from when you decompose calcium acetate into acetone, it undergoes a state where its liquid..
adding carbon to it at that point might work.. but i didnt have any luck with it yet.. somehow it apparently is capable of going into CaCO3 or CaO..
otherwise just go on ebay.de and search ''wühlmausgas''
http://www.ebay.de/sch/i.html?_nkw=w%C3%BChlmausgas&_sac...
|
|
|
nora_summers
Harmless
Posts: 34
Registered: 11-11-2010
Member Is Offline
Mood: I am figment of your imagination.
|
|
Can you get pure calcium metal? Maybe you can grind it up with carbon powder and then heat it to form calcium carbide.
|
|
|
Random
International Hazard
Posts: 1120
Registered: 7-5-2010
Location: In ur closet
Member Is Offline
Mood: Energetic
|
|
You would need very high temperatures, much easier to obtain it than to make it.
|
|
|
franklyn
International Hazard
Posts: 3026
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline
Mood: No Mood
|
|
• You can buy small amounts of CaC2 on ebay for not too much money
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=15098...
• Acetylene (ethene) is made by warming Chloroform with Silver powder
2 HCCl3 + 6 Ag => 6 AgCl + C2H2
The silver is reconstituted by heating the AgCl with a solution of formaldehyde
and a few drops of alkali, or with glucose or sugar and alkali, metallic silver is
obtained in a finely divided state again.
• Acetylene is also obtainerd by heating Tetrachloroethane with Zinc
Cl2CH.CHCl2 + 2 Zn => 2 ZnCl2 + C2H2
• It's also derived from Dichloroethylene and Sodium metal
ClCH:CHCl + 2 Na => 2 NaCl + C2H2
• From Propargyl Aldehyde ( Propiolaldehyde ) and Sodium Hydroxide
CHΞC-CHO + NaOH => HCOONa + C2H2
Propargyl Aldehyde can be made by dehydrating Propargyl alcohol with H2SO4
www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0813
• Acetylene is electrolytically formed from electrolysis of molten Fumaric acid
(287 ºC) or its sodium salt, and also from it's water soluble isomer called
Maleic acid which melts at 138 ºC, or from other unsaturated dibasic acids.
C2H2(COOH)2 => 2 CO2 + H2 + C2H2
A Dictionary of Applied Chemistry vol I , 1912 ( see page 25 )
http://books.google.com/books?id=vb8GAQAAIAAJ
A Dictionary of Applied Chemistry vol I , 1921 ( see page 39 )
http://books.google.com/books?id=MAA5AAAAIAAJ
Acetylene, The Principles Of Its Generation And Use
http://books.google.com/books?id=EFjkAAAAMAAJ , 1903
www.gutenberg.org/ebooks/8144 , 1909
http://archive.org/details/cu31924031240850 , 1910
click " All Files: HTTPS " at left side for download options
_____________________________________________________
Experimental
http://www.sciencemadness.org/talk/viewthread.php?tid=13144#...
Related Thread
http://www.sciencemadness.org/talk/viewthread.php?tid=2492
.
[Edited on 21-1-2013 by franklyn]
|
|
|
IrC
International Hazard
Posts: 2710
Registered: 7-3-2005
Location: Eureka
Member Is Offline
Mood: Discovering
|
|
| Quote: Originally posted by Fusionfire | | What I like about electric discharge through CaO + C is that not only are the raw materials dirt cheap, you don't have to fiddle about to get pure
CaC2 if you're just after acetylene - just add water |
I would be mindful of the fact if this reaction has exposure to air, nitrogen will be combined to form a percentage of Calcium Cyanamide. Probably Co
as well. Chemistry is not my specialty so one of the experts may want to comment on my thoughts. Also I have to wonder if Calcium Cyanide would not
also be yet another byproduct.
http://en.wikipedia.org/wiki/Frank%E2%80%93Caro_process
http://portal.acs.org/portal/acs/corg/content?_nfpb=true&...
"Science is the belief in the ignorance of the experts" Richard Feynman
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
